Kristen Bell and Rachel Bilson Tee Up for Invisible Children

In spite of Kristen Bell‘s busy acting career, the Couples Retreat star still took the time to make saving the world look stylish. Last week, Bell joined Pete Wentz and Rachel Bilson to co-host the Guess/Vanity Fair party in Los Angeles to launch special edition organic Guess T-shirts that benefit the nonprofit organization Invisible Children. Pairing one of the T-shirts with a sexy Vena Cava dress and Christian Louboutin pumps, Bell talked to PEOPLE about her involvement with the organization, which promotes youth education and economic development in war-torn regions of Central East Africa. “It’s just standing up for humanity, which I think is really important for us to do for each other,” she said. Bilson agreed, saying, “It’s also important to spread the word about these T-shirts. You can buy them, and all the proceeds go to Invisible Children.” The party stayed lively with Wentz behind the DJ booth and attendance by celebrity friends such as Annalynne McCord and Eliza Dushku with boyfriend Rick Fox. Buy your own Guess Invisible Children T-shirt for $26 on Guess.com, with 100% of the proceeds going to the organization. –Susan Yara